Conventionally, humidity control systems for controlling the humidity of air by using an adsorbent are known in the art. Patent Document 1 discloses a humidity control system having adsorption heat exchangers having an adsorbent supported on their surfaces.
The humidity control system disclosed in Patent Document 1 is provided with a refrigerant circuit having two adsorption heat exchangers. This refrigerant circuit alternately performs two operations: an operation in which a first adsorption heat exchanger serves as a condenser, and a second adsorption heat exchanger serves as an evaporator; and an operation in which the second adsorption heat exchanger serves as a condenser, and the first adsorption heat exchanger serves as an evaporator. In the adsorption heat exchanger operating as an evaporator, moisture in the air is adsorbed by the adsorbent. In the adsorption heat exchanger operating as a condenser, moisture is desorbed from the adsorbent into the air.
The humidity control system disclosed in Patent Document 1 supplies one of air streams that have respectively passed through the adsorption heat exchangers, into the room, and discharges the other air stream out of the room. For example, when the humidity control system is in a dehumidification mode, air flow paths in a casing are determined so that an air stream, which has passed through one of the first and second adsorption heat exchangers operating as an evaporator, is supplied into the room, and an air stream, which has passed through the other adsorption heat exchanger operating as a condenser, is discharged out of the room (see FIGS. 4 and 5 of Patent Document 1).
The humidity control system disclosed in Patent Document 1 also ventilates the room. For example, when in the dehumidification mode, the humidity control system supplies intake outside air into the room after dehumidifying the air in the adsorption heat exchanger operating as an evaporator, and, at the same time, discharges intake room air out of the room, together with moisture desorbed from the adsorption heat exchanger operating as a condenser.